Recent years have shown a proliferation in the functionalities that are offered by cloud services, as well as the number of individuals who subscribe to these cloud services. To subscribe to a cloud service, an individual typically operates a primary computing device (e.g., a smartphone) that is configured with a user account known to the cloud service. The individual can also operate auxiliary computing devices that are configured with the same user account known to the cloud service, thereby enabling the user to achieve the benefit of useful functionality such as synchronization of the user's data across his or her computing devices. In most cases, a public key (PKUser) and a private key (SKUser) are generated in accordance with the information of which the user account is comprised, e.g., a username and a password, where PKUser is used as a primary/root key for encrypting the user's data within the cloud service. In this manner, a possession of SKUser enables the user's data to be decrypted, which means that special attention must be paid to the manner in which SKUser is managed by the cloud service. This can also present challenges when attempting to enable different users of the cloud service to securely share data between one another.